Erosion barrier method and apparatus

ABSTRACT

An erosion barrier wastewater treatment system and in particular a liner for a wastewater treatment lagoon that provides for trapped gas below the barrier to be released through vents within the barrier and in particular to a liner for a wastewater treatment lagoon that may have portions replaced without operation of the wastewater lagoon facility being interrupted.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part and claims the benefit of U.S. application Ser. No. 12/956,662 filed Nov. 30, 2010 entitled Erosion Barrier Method and Apparatus which is hereby incorporated in by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to an erosion barrier wastewater treatment system that provides for trapped gas below the barrier to be released through vents within the barrier and in particular to a liner for a wastewater treatment lagoon that may have portions replaced without operation of the wastewater lagoon facility being interrupted. The lagoon may be any earthen basin for containing a body of water, for instance wastewater, and the liner is utilized mainly for reducing the erosion of the lagoon walls due to water turbulence.

BACKGROUND OF THE INVENTION

Conventional lagoon based wastewater treatment systems rely generally on open air lagoons to permit aerobic and anaerobic treatment of wastewater. A lagoon is any earthen basin for containing a body of water, such as a treatment reactor cell. Lagoons and other wastewater treatment ponds or basins are typically constructed by excavating land to create a reservoir area. If desired, berms can then be built around the perimeter of the reservoir area to extend the walls of the reservoir above ground level. Quite often, a lagoon is lined with a layer of clay to serve as a barrier. For example, environmental regulations typically require a subgrade clay layer of uniform thickness, for example 5 feet thick and having uniform water content. Often times a plastic liner made of high-density polyethylene may be placed over the entire interior surface defined by the reservoir and the berm area. The liner is made of sheet strips of high density polyethylene (HDPE) which overlap in an abutting fashion and are then welded or cemented together to create a water impermeable and erosion control line.

Once the lagoon is constructed and lined the wastewater liquid or sludge material is then pumped into the lagoon on top of the liner and/or the clay which is lining the lagoon. This liner facilitates not only maintaining the wastewater in the reservoir or lagoon but also in maintaining any turbulent water flow in the surface from eroding the berm and banking of the lagoon. The lagoon or pond is the subject to water fluid level changes as well as a turbulence of the surface in particular from aeration of the wastewater which can erode the banking and the berm. The liner is instrumental in protecting the underlying clay and soil lining forming the lagoon particularly where the turbulent water contacts the berm and banking.

Lagoon based water treatment systems require a large amount of space, on the order of several acres and often necessitate the large interior encompassing liner in conjunction with the lagoon construction to facilitate containment of the wastewater and to prevent erosion of the banking around the lagoon. This is tremendously expensive where an entire lagoon system must be covered with a liner, not only upon initial construction but upon replacement or fixing of a compromised liner.

Such traditional lagoon-based liner systems have several shortcomings. Because of the large size of the liners where the liners cover the entire interior of the lagoon, the liners which are generally impermeable material must be constructed on-site usually in large strips, where the strips are heat sealed together along their edges after being placed in an empty lagoon. This of course means that the lagoon must be emptied and cannot be used for the time period in which the new liner material is placed inside. It is tremendously labor intensive, time-consuming and expensive to assemble such liners and empty the lagoons if a liner needs to be fixed or replaced. Traditional lagoon based liner systems may further suffer from rippling because of either aeration or the decomposition of organics in the soil that builds up air and gas below the liner and that prevents the liner from lying flat on the soil. This rippling may cause further erosion where gaps between the liner and soil surface cause pathways for water to seep into and under the liner, removing soil as the water runs down the embankment.

SUMMARY OF THE INVENTION

The liner system of the present invention is a significant savings in material and man-hours to implement because the lagoon does not need to be drained, or operation even interrupted in most cases to construct and implement the erosion liner system. The liner is in effect a skirt which entirely surrounds the lagoon but does not need to extend and cover throughout the entire interior surface area of the lagoon. However, it is to be appreciated that the liner may extend to any length necessary to cover an interior surface as required. The skirt may be placed around the outside edge, banking and berm of the lagoon so that there is no down time for the wastewater treatment facility. Also, the panels of the skirt may be fit together by a simpler less labor intensive means because the edge of one panel does not have to be sealed to the edge of a second panel such as in the prior art liners. Instead a reinforced webbing strip is used to seal and secure the edge boundaries of each panel of the barrier.

In general the skirt is manufactured in manageable sections for instance in 50×20 foot rectangular sections which can be manufactured off-site, brought to the site and connected to the webbing strips along their edges with stainless steel bolts. The webbing strips may be of a heavier material to secure the side edges of each section and assist in preventing erosion and ensuring that such erosion does not occur along the top of the lagoon wall and embankment where turbulence from aeration or other mechanical processes to the wastewater may erode the lagoon banking or berm. The liner of the present invention may further be maintained substantially in contact with the banking of the lagoon through the opening of one or more vents within the liner. As air and gas due to aeration or decomposition of organics builds up below the liner, the vent will open to discharge the air and gas preventing rippling and air gaps between the under surface of the liner and the embankment.

These and other features, advantages and improvements according to this invention will be better understood by reference to the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Several embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings in which:

FIG. 1 is a diagrammatic representation of a wastewater treatment plant;

FIG. 2 is a cross section of a lagoon;

FIG. 3 is a first embodiment of a panel of the present invention;

FIGS. 4A-4B are further embodiments of a panel of the present invention;

FIGS. 5A-5B are embodiments of a corner panel of the present invention;

FIGS. 6A-6C are further embodiments of a panel of the present invention;

FIG. 7 is the affixed panels of FIGS. 6A-6C;

FIG. 8 is a diagrammatic plan view of an embodiment of a plurality of panels of the present invention;

FIG. 9 is a perspective view of a lagoon with an embodiment of the present invention; and

FIG. 10 is a cross section of an embodiment of a panel of the present invention.

FIG. 11 is a diagrammatic view of a further embodiment of a panel of the present invention having vents;

FIG. 12A is an elevation view of the further embodiment of the panel showing the vent of FIG. 11 in a closed position;

FIG. 12B is an elevation view of the further embodiment of the panel showing the vent of FIG. 11 in an open position;

FIG. 13A is a diagrammatic view of further embodiments of panels with further embodiments of the vents of the present invention; and

FIG. 13B is a diagrammatic view of an embodiment of a cover of the vent in a further embodiment of the panel of FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagrammatic representation of a wastewater treatment plant having a pretreatment process 110, a primary treatment process 120 and a secondary treatment process 130. The pretreatment 110 removes heavy materials such as trash, leaves, branches, etc., that can easily be collected from raw wastewater before damage is caused by clogging pumps or skimmers in the primary and secondary treatment processes. Pre-treatment may include screening the wastewater for such heavy materials by use of a screen or a rake passed through the wastewater to accumulate the heavier material on the screen which can then be removed manually or mechanically. Also, the flow of the wastewater may be adjusted to allow settlement of sand gravel, stones and broken glass for example. Particles of this type or kind can also damage pumps and other equipment in the treatment facility.

In primary treatment 120 the wastewater generally flows into large tanks called clarifiers, or sedimentation tanks, and these are used to initially settle sludge and to allow grease and oil accumulating on the surface to be skimmed off. The primary treatment 120 can include settling tanks equipped with the mechanically driven scrapers to drive the sludge towards a hopper in the base of the tank and skimmers at the surface for collecting the grease and oil, often times referred to as sapofication.

The wastewater is then transferred generally via a pump to a secondary treatment process 130 which often entails a lagoon or pool where most conventional water treatment facilities use aerobic biological processes to break down the biological materials in the wastewater. These aerobic processes require sufficient oxygen and food so that this aeration can take place for example in the lagoon. The aerators are often motor driven aerators floating on the surface of the wastewater in the lagoon. This aeration often causes significant turbulence on the surface of the water which then of course propagates outwards to the edges of the lagoon. Over time this turbulence can wear away the banking and berm potentially compromising the lagoon. The liner and fasteners described in further detail below ensure that such turbulence does not erode the banking of the lagoon and that installation of this device does not impact the operation or efficiency of the lagoon.

FIG. 2 is a cross-section of a lagoon 10 with the cross-hatching indicating a soil layer 12 which can be a clay layer or other type of porous, semi-porous or non-porous soil defining the lagoon itself. The lagoon 10 has a bottom 14, a banking or embankment 16 and built up to form a rim around the lagoon 10 is a berm 18 which helps contain the wastewater 22 in the lagoon 10. A lagoon liner 24 of the prior art is set in place covering the entire interior surface area of the lagoon 10 and the berm 18. As shown in FIG. 2 the liner 24 stretches across the entire bottom 14, embankment 16 and berm 18 of the lagoon 10 and is fastened to a retaining wall 26 which encircles the lagoon 10 and supports the berm 18. The embankment 16 and berm 18 may be at any slope and commonly a trench 28 is built within which the retaining wall 26 is positioned.

An aerator 32 may be positioned in the lagoon 10 to supply oxygen to the wastewater 22. An ample oxygen supply in a wastewater lagoon is the key to rapid and effective wastewater treatment. Oxygen is needed by the bacteria to allow their respiration reactions to proceed rapidly. The oxygen is combined by the bacteria with carbon to form carbon dioxide. Without sufficient oxygen being present, bacteria are not able to quickly biodegrade the incoming organic matter. In the absence of dissolved oxygen, degradation must occur under septic conditions which are slow, odorous and yield incomplete conversions of pollutants. Under septic conditions without aeration, some of the carbon will react with hydrogen and sulfur to form sulfuric acid and methane. Other carbon will be converted to organic acids that create low pH conditions in the ponds and make the water more difficult to treat. For example, treated ponds designed to biodegrade wastewater pollutants without oxygen often must hold the incoming sewage for six months or longer to achieve acceptable levels of pollution removal. This is because the biodegradation of organic matter in the absence of oxygen is a very slow kinetic process.

Motor driven, mechanical aerators provide a combination of liquid aeration and mixing. Some mechanical aerators produce the gas-liquid interface by entraining air from the atmosphere and dispersing it into bubbles. Other types disperse liquid in the form of droplets or they produce jets or thin films as a spray that contact the ambient air. Some other types even generate both liquid droplets and air bubbles. Mechanical aerators create turbulence on the surface of the pond, this turbulence is beneficial in that turbulence facilities gas-liquid interface however, the turbulence has consequential side effects where the turbulence reaches to the banking and berms of the lagoon and creates erosion where no liner is utilized. Until now, the only solution to such erosion has been to ameliorate the effects by using a full lagoon liner as shown and described in FIG. 2.

Turning to FIG. 3, a single panel 30 of the present invention is shown having a substantially rectangular shape defined by a top edge 33, a bottom edge 34 and opposing side edges 36. The top and bottom edges 33, 34 are reinforced with 2 inch nylon webbing 35 sewn along the entire length of the panel 30 and the side edges 36 are similarly reinforced with 3 inch nylon webbing 39 sewn along each the length of the sides 36. Other sizes and material reinforcements may be used as well. The side edges 36 are further provided with a plurality of grommets 38, for example stainless steel grommets, defining holes in and through the nylon webbing 39 and panel material. These holes align with the holes on adjacent panels and provide fastening points through which fasteners, such as stainless steel nuts and bolts for example, can secure adjacent panels 30 together.

Along the entire bottom edge 34 of the panel 30 is a pocket 40 sewn into the panel by overlapping the lowermost edge of the panel on itself and sewing the lowermost edge along a stitch line 41 to define the pocket 40. The overlap of the lowermost edge 34 can be in the range of about 1-3 inches so that the pocket 40 can accommodate a ½ to 1 inch chain or other ballast 42 inserted into the pocket 40 along the entire bottom edge 34 of the panel. The chain or ballast 42 is stretched through the pocket 40 so that the weight of the chain 42 is essentially uniform along the length of the panel 30 and so that the panel lies evenly and uniformly along the berm 18 and banking 16 of the lagoon 10 as described in further detail below. The reinforcing nylon webbing 44 at the bottom edge of the panel 30 is, in one embodiment, sewn in conjunction with the stitch line 41 which defines the overlap and joining of the lowermost edge of the panel 34 to the panel to define the pocket 40. Thus the pocket 40 actually hangs below the nylon webbing 44 at the bottom edge 34 of the panel 30. This arrangement of the lower reinforcing nylon webbing 44 is important because the panel 30 is most susceptible to failure along the stitch line 41 which defines the pocket 40. While there is some potential wear of the panel 30 material along the pocket portion of the panel 30, a hole or abrasion here which exposes the chain or ballast 42 will not cause failure of the panel 30. On the other hand failure of the stitching along the pocket 40 can compromise the entire pocket 40 and permit the chain or ballast 42 to fall entirely out of the pocket.

It is to be appreciated that lagoons may be of any size and shape, but are generally circular, square or rectangular. The size and shape of different lagoons may determine the specific size and shape of the panels used in a certain lagoon. For example as seen in FIGS. 4A and 4B a variety of shapes may be formed to accommodate corners, lengths and angles of various shaped lagoons. In FIG. 4B a side edge 37 of a corner panel 41 may be cut at an angle, here a 45 degree angle, to mate with a similar angled side edge 37 of an adjacent corner panel 41 to complete the right angle corner as shown in FIG. 5A. Alternatively a complete corner panel 43 may be sewn and reinforced with webbing 45 along an angled intermediate stitch line 49 as seen in FIG. 5B so that the side edges of the corner panel are at 90 degrees relative to one another.

An alternative panel shape shown in FIG. 6A shows the panel 53 in another embodiment being trapezoidal in nature to account for the slope and change in diameter between the upper most lip of a lagoon and a point lower down on the banking 16 where the bottom edge 54 of the panel rests. The diameter of the lagoon changes as the banking or embankment 16 slopes down into the lagoon and has a smaller diameter than that of the upper lip of the bank or berm 18. To determine the appropriate trapezoidal shape for such a panel, the difference between the length of the circumferential top lip 52 and the circumferential length y of the desired banking point where the bottom edge 54 of the panel will lie, is determined by any conventional measurement process. This difference, divided by the number of panels required to encircle the lagoon, gives the approximate unit of measurement difference between the top edge length t and the bottom edge length b for each panel required to circumscribe the lagoon or pond and account for the slope of the banking 16 and berm 18. An intermediate panel 51 shown in 6B may be formed with a first side edge 47 that matches the side edge 47 of the trapezoidal panel 53 and a second straight edge 36 that matches the side edge of a panel 30. The side edge 47 of the trapezoidal shape of panel 53 and the intermediate panel 51 may be at an angle of 0 to 45 degrees to match the measurement difference of the top edge t to the bottom edge b of a required corner or rounded banking of the lagoon. The top edge 56 and bottom edge 58 of the intermediate panel may be of any length that maintains a flat seam along the side edge 36 and side edge 47. The intermediate panel 51 may mate with the trapezoidal panel 53 and the rectangular panel 30 as shown in FIG. 7. Flexibility in panel shape is an important aspect of the present invention thus allowing the panels to be closely aligned without creating rolls or ridges within the panel that could form gaps and cause water seepage and erosion below a panel.

Separate panels are secured together along adjacent side edges by overlapping the side edges and aligning the respective grommets and holes in the adjacent panels. One manner of securing the side edges is the insertion of a bolt through each aligned hole and securing of the bolt in the hole by a nut. The bolt head and nut of course being larger than the hole in the side edge of the panel. Other methods of fastening the aligned side edges of the panels such as with clips or other fasteners are also contemplated.

It is an important aspect of the present invention that the liner system and panels can be placed in position and into operation without having to interrupt operation of the wastewater treatment system and lagoon. Because, while it is to be appreciated that the panels may extend to any length within the lagoon, the panels do not need to extend entirely across and along the bottom of the lagoon, the entire circumferential ring of panels can be assembled around the edge of the lagoon and placed into position in the lagoon while the treatment plant or system continues to operate.

In FIG. 8 a diagrammatic plan view of a plurality of panels attached together and forming a complete ring for encircling a substantially rectangular lagoon is shown. A perspective view of a lagoon with an embodiment of the present invention is shown in FIG. 9. In these examples, trapezoidal panels 53 and intermediate panels 51 are used to enclose the corners of the rectangular lagoon and rectangular panels 30 cover the other portions of the lagoon berm 18 and banking 16. Each panel may be at only a short distance below the water's surface 48 or may extend further into the lagoon to any distance depending on the solubility of the banking 16 and the turbulence of water within the lagoon. The tops of the panels may extend over the retaining wall 26 and be secured within a trench 28 encircling the lagoon. Pretreatment sedimentation tanks 52 are also shown.

An embodiment of panel dimensions is shown in FIG. 10. As seen in this embodiment, a cross-section of the panel has a first portion of the panel which is secured within the trench 28 and extending up and around the retaining wall 26 along the circumference of the lagoon. Where a panel is provided for example with a width of 20 feet, 3 feet of the width generally defines this first portion which is secured by entraining this first portion of the panel within a trench 28 under, and partially around the retaining wall. An intermediate section of approximately 2 feet extends across the top of the berm 18, and a majority of the panel of approximately 15′ then depends down the slope of the banking 16 into the lagoon where the bottom edge of the panel including the pocket 40 having the chain or ballast 42 therein. Again, because each panel comprising the liner can be attached to the adjacent panel and then positioned down into the lagoon even below the water level, the treatment and operation of the wastewater lagoon and facility is not interrupted.

In this way an erosion control lagoon liner can be constructed and implemented inexpensively and without interruption of facility operation for installation of the device. Additionally, a single panel can be easily replaced by disengaging the side edges removing the panel and replacing with a similar replacement panel, all without interruption of facility operation. One embodiment of the liner and panels involves the use of 3028 XR5® material a highly resistant, non-degradable membrane surface with extreme puncture and tear resistance as well as dimensional stability under high loads and extreme temperature fluctuations. Other containment and liner materials can be used as well.

In a further embodiment as shown in FIG. 11, using the same 3028 XR5® material or similar but of a thinner ply and of a lighter weight liner material, a vent 62 may be formed by cutting a hole or opening 64 through a panel 60 of the liner and covering the opening 64 with a separate piece of liner material that is larger in overall dimensions than the hole 64. This vent cover 66 may be secured to the liner panel 60 by affixing the cover 66 to the panel 60 only along an upper portion 68 of the cover 66. The cover 66 may be affixed to the panel 60 by stitching the material to the panel 60 forming a seam 70 or by using glue, adhesive or other water resistant compound to adhere the cover 66 to the panel 60. By attaching the cover 66 to the panel 60 only along an upper portion 68, gravity holds the cover 66 closed and in contact with the panel 60 as the liner is positioned on the vertical slope of the embankment 16. In further embodiments, the vent cover 66 may be adhered along more than the upper portion 68 such as partially along one or both sides of the cover 66 as necessary and as determined by the environment and the amount of slope of the embankment.

The vent cover 66 as well may be of any shape that is adequate to completely cover the opening 64 that is formed in the panel 60. For example as shown in FIG. 11, the hole 64 and vent cover 66 may each be formed in a square shape with the cover 66 having a dimensional area that is two to four times larger than the opening 64 through the panel 60. The upper portion 68 of the vent cover 66 may further be extended above the center line C of the opening 64 forming a rectangle with sides 72 that are longer in dimension than the upper edge 74 and lower edge 76 to provide for the seam 70 or adhesive to affix the cover 66 to the panel 60 with enough clearance from the opening 64 to not cause rips or tears within the liner material along the edge 78 of the opening 64 of the panel 60.

As shown in FIG. 12A, after the liner or erosion barrier panel 60 is in position along the embankment 16, air and gases A may build up under the panel 60 due to aeration or decomposition of organics in the soil. This build up of air and gases A forces the panel 60 to separate from surface of the embankment 16 and form pockets and ripples in the flat surface of the panel 60. As the pockets and ripples expand along the boundaries to the upper and side edges 33 and 36 of the panel 60 air gaps may form allowing rain water to enter through these gaps and to erode soil below the erosion barrier panel 60. As shown in FIG. 12B, by placing one or more vents 62 along the upper and/or side edges of the panel 60 the buildup of air and gases A will force the vent cover 66 away from the upper surface of the panel 60 and allow the air and gases A to escape from under the panel 60. This expulsion of air and gases A provides for the panel 60 to settle and lay flat again against the surface of the embankment 16. By positioning the vents 62 towards the upper and side edges 33 and 36 of the panel 60 any gaseous build up is released at sufficient distances from these edges 33 and 36 preventing air gaps or fluid pathways to form below the panel and cause erosion of the embankment 16. After the expulsion of air and gases A, the vent cover 66 also drops and closes due to gravity and contacts the surfaces around the opening 64. The vent cover 66, may be of the same material and thickness as the panel 60 or be the same material of a thinner ply, or be a similar highly resistant, non-degradable membrane material but lighter than the material of the panel 60. In using a lighter material less pressure from the gaseous buildup is required to open the vent 62 and release the air and gases A. The release of the gases at lower pressures may help to minimize rippling of the material of the panel 60 where higher pressures would be required to form pockets or ripples in the heavier membrane surface of the panel 60. The amount of pressure to open the vent may also be set by using an adhesive with minimal adhesion so that only a small amount of force or pressure from the air and gases A is necessary to open the vent cover 66, while the adhesive also maintains contact of the vent cover 66 to the surface of the panel 60 in windy or harsh weather.

In an open position as shown in panel 60 of FIG. 13A, the vent may open only a small distance from the panel to expel the air and therefore because of the oversized dimensions of the cover 66, the hole 64 through the panel 60 is still substantially covered. The vents 62 as well may be positioned anywhere within the panel surface. In this embodiment the vents 62 are positioned closer to the upper edge 35 of the panel 60. In further embodiments, one or more vents 82 may be substantially centered within the panel as shown in panel 80 and depending upon the size of the panel, in further embodiments a series of vents 92 may be formed along the upper and side edges 33 and 36 as shown in panel 90. Therefore, based on the dimensions of the panel and the environment that the liner is used within, any adequate number of vents 62 may be placed throughout the panel 60 with the size of the opening 64 cut within the panel ranging in diameter from 5 cm (2 inches) to 15 cm (6 inches) and the vent cover 66 ranging in diameter from 10 cm (4 inches) to 50 cm (20 inches) and more specifically a 10 cm (4 inch) diameter opening 64 and 15 cm (6 inch) diameter cover 66 where both the opening 64 and the cover 66 are circular as shown for example in panel 80. Covers and holes that are not circular in shapes may be similarly to these sizes and dimensions.

The vent cover 66 may be of a different shape than the opening 64 as shown in panel 60 or the cover 66 and opening 64 may be of the same shape with an upper portion of the square, circular or rectangular shape cover sewn or otherwise attached to the panel. The opening 64 and the cover 66 may in fact be of any shape or dimension with a restriction being that the cover 66 is of a larger dimension than the opening 64 to completely cover the opening 64 so that water from rain or turbulence from the lagoon or tank is prevented by the cover 66 from entering the opening 64.

As shown in FIG. 12A, the panel 60 of the erosion barrier may be secured to the embankment by extending an upper portion 61 of the panel 60 over the berm 18 and upper edge of the embankment 13 and over the retaining walls 26 that form the trench 28. This extended portion 61 of the panel 60 is also of a sufficient extended length to provide for the upper portion 61 to be placed within the trench 28 and be moored or secured using one or more pins 63 that may be placed at locations along the trench at roughly every 100 cm to 250 cm (3½ feet to 8 feet) and more specifically at locations of roughly every 150 cm (5 feet). The pin 63 may be made of any environmentally resistant metal such as 304 stainless steel and may be approximately 0.95 cm (⅜ inch) in diameter and 30 cm (12 inches) in length. The pins 63 are driven into the ground at the bottom of the trench 28 through grommets 67 that may also be made of a similar material such as 304 stainless steel. The grommets 67 are of a larger diameter than the pins at approximately 1.25 cm (½ inch) and help to prevent tearing of the panel 60. The trench 28 may be approximately 60 cm (2 feet) deep and approximately 30 cm (1 foot) in width. After securing the panel 60 in place using a number of pins 63 the trench 28 is filled with soil 65 burying the upper portion 61 to hold the erosion barrier panel 60 in place. From the trench 28, a sufficient length of the panel 60 extends down and along the embankment to the lagoon 10 to substantially enclose the embankment 16 that is above the water level of the lagoon 10 and extend along a sufficient portion of the embankment 16 to be underwater with the chain ballast 42 within the pocket 40 at the base of the panel 60 aligning along the perimeter of the lagoon 10.

To further secure the erosion barrier in place, additional embankment pins 69 may be placed at approximately every 7.5 meters (25 feet) or more frequently along the bottom of the erosion barrier, dependent on the dimensions of the erosion barrier. The pins 69 may be of a similar diameter to the trench pins 63 approximately 0.95 cm (⅜ inch) but of a longer length at approximately 1 meter (3.28 feet) in length. The pins 69 as well are driven into the embankment 16 through grommets 67 that may also be made of a similar material such as 304 stainless steel and of a larger diameter than the pins at approximately 1.25 cm (½ inch) to help prevent tearing of the panel 60 and assist in securing the panel 60 to the embankment 16. The grommets 67 may be affixed to or pressed into the webbing or hem of the panel 60 to properly secure the panel 60 to the embankment 16.

In a still further embodiment, along the side 36 of each panel 60, an additional connecting strip of webbing 71 provides for a first panel 60 to be secured to a first side of the webbing 71 and a second panel 90 to be secured to a second side of the webbing 71. This provides for a first panel 60 to be detached from the webbing strip 71 without lifting or unsettling the second panel 90 thereby reducing gaps or rippling being formed in the second panel 90 during the replacement of the first panel 60. The webbing 71 may be in a range of approximately 15 cm (6 inches) to 30 cm (12 inches) in width and extend to a length that is approximately the same as the length of the side 36 of the panel 60. In a first embodiment, a series of grommets 67 are placed along the connecting strip 71 in similar location and dimension as the grommets 38 of the panel. A series of stainless steel bolts are inserted through both the panel grommets 38 and webbing strip grommets 67 and a series of stainless steel nuts are threaded onto the bolts to secure the webbing strip 71 to the panel. The webbing strip 71 may further be secured to the embankment 16 using similar embankment pins 69 with one or two pins with grommets 67 driven into the embankment along the lower portion of the strip 71. The webbing strip 71 may be made from a reinforced nylon and be of a thicker dimension and heavier than the erosion barrier material to provide for holding the barrier in place and to provide for the lower surface of the barrier to maintain continuous contact with the embankment 16 along each side of the barrier panel 60 preventing air gaps or rippling. By sealing the side edges of the barrier, any air or gaseous build up below the barrier will be directed through a less resistive path to the vents 62 to be discharged providing for the barrier to remain flat against the embankment 16.

The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. 

I/We claim:
 1. A pond or lagoon liner comprising: a plurality of panels fastened together to define a ring which circumscribes the pond or lagoon; each panel comprising: a top edge, a bottom edge and opposing side edges; a pocket formed at the bottom edge of each panel; a ballast supported in the pocket of each panel; a vent formed in the panel; and wherein the vent opens to release air and gas build up from under the liner.
 2. The pond or lagoon liner as set forth in claim 1 wherein the vent is of a material that is lighter in weight than the liner.
 3. The pond or lagoon liner as set forth in claim 1 wherein the vent having a cover that is larger in dimension and covers an opening in the liner, the cover being adhered to the upper surface of the liner.
 4. The pond or lagoon liner as set forth in claim 1 further comprising an upper portion of the panel that is secured within a trench and buried with soil to secure the liner in place.
 5. The pond or lagoon liner as set forth in claim 1 further comprising a plurality of fastening points spaced along the opposing side edges of each of the plurality of panels and a plurality of webbing strips having a plurality of fastening points comparably spaced to the panel fastening points; and wherein a webbing strip secures a first panel to a second panel using the plurality of comparably spaced fastening points and a first panel may be replaced by detaching the first panel from the webbing strip without disturbing the second panel from an embankment of the pond or lagoon.
 6. The pond or lagoon liner as set forth in claim 5 wherein the plurality of panels are fastened together using the plurality of webbing strips and the liner is positioned in the pond or lagoon without emptying the pond or lagoon of fluid.
 7. The pond or lagoon liner as set forth in claim 5 wherein the plurality of panels are fastened together using the plurality of webbing strips and the liner is positioned in the pond or lagoon without interruption of facility operation.
 8. The pond or lagoon liner as set forth in claim 1 further comprising a reinforcing webbing applied along the top edge, bottom edge and opposing side edges of each panel to further reinforce the liner encompassing the pond or lagoon.
 9. The pond or lagoon liner as set forth in claim 8 wherein the pocket is formed on the bottom edge of each panel by overlapping a lowermost edge of each panel and affixing the lowermost edge along a length of the panel.
 10. The pond or lagoon liner as set forth in claim 9 wherein the reinforcing webbing applied along the bottom edge facilitates the support and the affixing of the lowermost edge to the panel in defining the pocket for the ballast.
 11. A method of preventing erosion in a fluid treatment pond or lagoon comprising the steps of: fastening together a plurality of panels using a plurality of connecting strips of webbing; fabricating each panel having a top edge, a bottom edge and opposing side edges; forming a pocket at the bottom edge of each panel; supporting a ballast in the pocket of each panel; forming a plurality of vents in at least one panel; and wherein the plurality of panels are positioned along an embankment of a lagoon and at least one of the plurality of vents opens to discharge gaseous build up from under the plurality of panels to maintain the lower surface of each of the plurality of panels in continuous contact with the embankment to prevent erosion of the embankment.
 12. The method of preventing erosion in a fluid treatment pond or lagoon as set forth in claim 11 further comprising the step of applying a reinforcing webbing along the bottom edge to facilitate support and affixing of a lowermost edge to the panel in defining the pocket to support the ballast.
 13. The method of preventing erosion in a fluid treatment pond or lagoon as set forth in claim 11 further comprising the step of positioning the liner in the pond or lagoon without emptying the pond or lagoon of fluid.
 14. The method of preventing erosion in a fluid treatment pond or lagoon as set forth in claim 11 further comprising the step of burying the top edge of each panel in a trench above a fluid surface level in the pond or lagoon.
 15. The method of preventing erosion in a fluid treatment pond or lagoon as set forth in claim 11 further comprising the step of installing the liner in the pond or lagoon without interruption of facility operation.
 16. The method of preventing erosion in a fluid treatment pond or lagoon as set forth in claim 11 further comprising the step of replacing a panel of the liner by disconnecting only the panel to be replaced from a connecting strip of webbing without unsettling an adjacent panel also attached to the connecting strip of webbing. 